328 



FISHES. 



Crossorhinus. — The first dorsal behind the ventrals, the second 

 in advance of the anal, which is very close to the caudal. Tail 

 rather short. Eyes small. Spiracle a wide oblique slit, behind 

 and below the eye. Nasal and buccal cavities confluent. Head 

 broad, flat, with the snout very obtuse ; mouth wide, nearly 

 anterior. A free nasal cirrhus ; sides of the head with skinny 

 appendages. Anterior teeth rather large, long and slender, 

 without lateral lobes, the lateral tricuspid, smaller, forming a few 

 series only. The fourth and fifth gill-openings close together. 



Three species are known from the Australian and Japanese 

 coasts. They are evidently ground-sharks, which lie concealed 

 on the bottom watching for their prey. In 

 accordance with this halut their colour closely 

 assimilates that of a rock or stone covered 

 with short vegetable and coralline growth — a 

 resemblance increased by the frond-like ten- 

 tacles on the side of the head. This peculi- 

 'lillli arity of the integuments, which is developed 

 in a yet higher degree in Pediculati and 

 Lopliobranchs, is not met with in any other 

 Selachian. These Sharks grow to a length of 

 10 feet. 



Sixth Family — Hybodontid.e. 



Two dorsal Jins, each icith a serrated spine. 

 TeetJi ro muled, lonfjitudinally striated, witli one 

 leirgcr, and from tiro to four smaller latered 

 cusps. Skin covered icitli shagreen. 



Extinct. From carboniferous, liassic, and 

 triassic formations. Several genera have been 

 distinguished ; and if Cladodus belongs to this 

 family, it would have been represented even 

 in the Devonian. 



Fig. 118. — Spine 

 of Hybodiis %\\h- 

 cariiiatus. 



Seventh Family — Cestraciontid^. 

 Ko nictitiding meinhrane. Tu-o dorsal fins, the first 



